I know there is a paid support option for Vector Linux. Customers who would want to use it as application server platform will, most likely, need those features very much. With UNIXodbc or iODBC one could write PHP application which works with Oracle database on another machine or even with Microsoft SQL server on some Windows server.

It is not such a big deal, one could use proper pre-built Bitnami stack, which is also quick and easy to deploy. However, usually, those options exist in quite a few other distributions (Red Hat, OpenSUSE, Debian - those are ones I worked with).

Your typical "LAMP" setup is MySQL or MySQL fork like MariaDB. The reason PostgreSQL isn't used is it tends to be slower than MySQL. In a hosted environment, especially on shared servers, this can be a killer.